Improvement in scroll-chucks



s. n. wescor.

Scroll Chucks.V

* Patented Feb.16,1875.

vkill-essay JOHN H. WESTOOTT, OF ONEIDA, NEW YORK.

IMPROVEMENT IN SCROLL-CHUCKS.

Specihcation forming part of Letters Patent No. l 59,959, dated February 16, 1875; application tiled December 10, 1874.

To all whom t may concer-n:

Be it known that I, JOHN H. WESTGOTT, of Oneida, in the county of Madison and State of New York, have invented'an Improvement in Scroll-Chucks; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the aceompan ying drawings, forming part of this speciiication.

My invention relates to cert-ain improvements in scroll-chucks, such as are well known and in ordinary use 5 and it consists in a novel construction of the scroll and box, whereby the threads are kept cleared and prevented from clogging.

In scroll-chucks as heretofore constructed, threads 0n the face-plate and the boX carrying the dogs have been formed with their ends tapering, the ends of the thread of the scroll having been so formed by the meeting of the volute of the thread with the inner and outer concentric circles ot' the scroll-plate. This formation has produced more or less ot' a wedge-like action upon any dirt which might accumulate between the threads, which have thereby been liable to become clogged and cause inconvenience in handling` the chuck. This evil is remedied in my invention, which I will proceed to describe with reference to the accompanying drawing, in which- Figure l is a face view ot' the scroll-plate. Fig. 2 is a sectional view ot' the same, taken in the line a x of Fig. l. Fig. 3 is a sectional view taken in the line y y of Fig. l. Fig. 4 is a sectional view, showing the scroll-plate and bei; engaged with each other. Fig. 5 is a face view of the box. Fig. G is a side View of the The scroll or face-plate A is of similar c011- struction to those in ordinary use heretofore, except that its thread a has both its inner and outer ends cut square across at right angles with its length, so that the ends of said thread are ot' the same Width as the other portion, which is uniform throughout. The boX B is formed with sectional threads b, for engagement with the scroll-thread c. rlhe inner one b1, and outer one b2, ot these sectional threads are of uniform width throughout, having' their ends cut square across, as shown in Figs. 5 and 6. The intermediate threads may, it' desired, have their ends tapering or wedgeshaped.

In scroll-chucks of ordinary construction, the tapering ends ot' the threads as they engage with each other, have a tendency to Wedge the dirt in the spaces between the threads, and thus clog the parts and prevent the successful working of the saine.

By cutting the threads square across, so as to make the ends of the same thickness as the other portion, and ofthe same thickness as the space between the threads, the square ends force the dirt ahead and clear out the grooves, and thus eft'ectually prevent clogging.

Vhat I claim as new, and desire to secure by Letters Patent, is-

The scroll or face-plate A, and boXes B, each having their threads a and b1 b2 constructed with their ends square, or at right angles to the length of the thread, vas herein shown and described.

JOHN H. WESTOOTT.

Witnesses:

T. F. HAND, Jr., A. HAwKlNs. 

